For many years amalgam has been used extensively in the restoration of human teeth. The amalgam is an alloy of mercury and other metals such as silver, tin, copper and zinc. The amount of mercury in these types of amalgam is mainly from about 50 to about 70%, by weight.
Recent studies have demonstrated that metallic mercury is released from the amalgam as a vapor in the human mouth. This emission of mercury vapor is a continuing, ongoing process, but the amount released per second demonstrates significant fluctuations, depending upon several factors, such as the temperature of the amalgam filling, and whether the filling is exposed to abrasion, such as chewing, brushing, grinding or other types of mechanical force. Accordingly, several studies have shown that the emission of mercury vapor increases significantly during periods of chewing or the like, when compared to periods of no mechanical stress.
In the publication "Striden om amalgamet", page 21 Kalla 33, by the Swedish Federal Research Department report from 1989, measurements are reported of this emission of mercury vapor. Apparently, these measurements are made on the total exhaled air from test persons and are, accordingly, demonstrating "diluted" sum numbers from all the teeth in each person's mouth. Reported results are shown in FIG. 1. In this Figure, curve I shows a series of measurements made on eleven test persons without amalgam fillings. Curve II shows a series of measurements made on nine test persons, wherein each person has up to four amalgam fillings on the occlusal surfaces. Curve III shows a series of measurements made on ten test persons, wherein each person has more than ten amalgam fillings on their occlusal surfaces. The curves show how the emission of mercury vapor measured in micrograms per cubic meter of the exhaled air varies in time when the test persons are chewing.
Curve I of FIG. 1 also shows that test persons with no amalgam filling in their teeth still emit a small amount of mercury vapor, and this amount is not influenced by chewing. Such emission is probably due to the presence of mercury deposited in the human body through means other than amalgam fillings, and is continuously emitted.
From curve II of FIG. 1, it can be seen that the amount of mercury vapor in the exhalation air increases sharply and very quickly when chewing is started. Further, even after chewing has ceased for 30 minutes, the amount of mercury vapor only slowly decreases toward the starting value. Curve III of FIG. 1 demonstrates a very sharp increase in the emission of mercury vapor. The maximum values after 30 minutes of chewing are many times higher than the starting point before the chewing was initiated. Further, the increased values remain during a long time after completed chewing. Since the emitted mercury vapor probably, at least partly, is absorbed by the human body, a potentially significant health risk is presented.
A need therefore exists for a method by which the amount of mercury and mercury vapor emitted from dental amalgam may be eliminated or reduced so that the amount of mercury being exposed to the human body can be made significantly reduced. Further, a need exists for a composition that is capable of significantly reducing the emission of mercury vapor from mercury-containing amalgam fillings.